Method and Device For Disinfection and/or Purification Of A Product

ABSTRACT

The present invention relates to a method and device for illuminating and at the same time purifying or disinfecting products such as air, flowers, food, vegetables, meat, poultry or fish. The method comprises the use of IR emitting LED elements.

PRIORITY CLAIM

This application is a continuing application of U.S. patent applicationSer. No. 13/265,650 filed on Dec. 20, 2011 and claiming priority ofPCT/EP2010/055276 filed on Apr. 21, 2010 and NL1036892 filed on Apr. 21,2009. Each of these documents is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to method and device for purification ordisinfection of products using infrared light. In particular, it relatesto the purification or disinfection of fresh produce, liquids, air andsolids using infrared light.

BACKGROUND OF THE INVENTION

Purification methods using light, in particular UV light are known andaccepted in industrial application since long. For instance in sewagestations, it is known to purify spoiled water using UV light in the formof long tubes, e.g. included in racks that are lowered in a water streamfor longitudinal passage of water. Another application for “exteriordisinfecting” of produce products is known from patent publication U.S.Pat. No. 132,784.

Patent publication WO2005031881 indicates disinfecting such as for waterpurification may also be performed by LED lamps, the advantage being “anappreciably superior effectiveness” over “disinfecting lamps knowntoday—2004—(TUV, HOK and DBD)”. This invention uses UV light. Othertypes of disinfecting lamps are recently proposed through the use ofinfrared or near infrared light. One example, from U.S. Pat. No.6,030,653, discloses the use of visible or infrared light for coldpasteurisation a food product. The visible or near infrared lightillumination always has to be preceded by illumination with nearinfrared light to create an optical window. A method and device usingLED for purification of water are known from the PURE RAY™ “pdfpublication “water purification” as available onwww.gobalwarmingsolutions.com. This publication teaches the use ofinfrared light for purification purposes as being a relatively low costpurification method. In order to realise this method, infrared lightover a wavelength from 810 nm to about 1300 nm is emitted from a sourcelocated centrally within a coiled liquid transporting, transparent hose,towards liquid to be purified. The source may be a LED (light emittingdiode), connected to a power source and AC/DC converter. Pulsation isnot mentioned or suggested. Yet, a requirement to further technicaldevelopment is simultaneously recognised in both the known method anddevice for executing the same. It is therefore an object of the presentinvention to arrive to a generally applicable, highly effective methodusing LED components in a functional and economic manner, preferably ina manner applicable both in water purification as well as in livingtissue products like fresh produce, flowers, fish and the like.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for disinfecting or purifyinga product. The method comprises illuminating a product with infraredlight from one or more light emitting diodes.

One advantage of the present invention is that products are illuminatedand purified or disinfected at the same time. This is important atvarious locations, such as for example at retail shops for improvedillumination of flowers and fresh produce which is installed for sale.Using the method or device according to the present invention, suchdisplay for sale is improved in quality because the colours of theproduct are reflected correctly and the life of freshness of the productis elongated by the external and internal disinfection or purification.

A concomitant advantage is that freshness of products may be maintainedat the work station, while maintaining and even improving the humanvision at the work station in a safe way. This could not be achievedusing UV light, which is damaging to the human eye. Yet anotheradvantage is that using the method or device of the present invention,freshness may be maintained longer, not only in a conditionedenvironment, e.g. under cooled circumstances, but also outside aconditioned environment, due to the sanitary and respiratory impulse ofelimination according to the present invention.

In the present context, the terms ‘LED’, ‘LED element’ and ‘lightemitting diode’ are used interchangeably, and refer to light emittingdiodes in all known forms, be it inorganic, organic, point-like,line-like. In one embodiment, the LEDs are wide angle elements, whichrefers to

LEDs which deliver nicely spread light rather than spotlights. In thepresent context, the phrase ‘purifying or disinfecting a product’ refersto the reduction of the number of microorganisms present on or in aproduct. In the present context, the terms ‘infrared light’ and ‘IRlight’ are used interchangeably and refer to electromagnetic radiationof a wavelength in the range of about 700 to about 1000 nm.

In the present context, ‘white light’ refers to electromagneticradiation which is visible to the human eye and which has a wavelengthwithin the range of about 380 to about 800 nm. The term ‘warm whitelight’ refers to white light with a wavelength within the range of 425nm to 475 nm, preferably with the peak of emission around 455-465 nm,The term ‘cold white light’ refers to white light with a wavelengthwithin the range of about 500 nm to about 700 nm, with the peak ofemission around 600 nm.

According to the method of the present invention, the product isilluminated by IR light emitted by one or more LED elements. In apreferred embodiment, the IR light emitted by the LED is of a wavelengthwithin a range from 900 nm to 960 nm. Preferably, the light emitted bythe IR LED element has a wavelength of 940 nm.

In another embodiment according to the invention, the product isilluminated by a combination of IR light and white light. The IR lightand white light are typically emitted simultaneously and by separateLEDs. Preferably, the LEDs emitting white light comprise LEDS emittingcold white light and LEDs emitting warm white light. In a preferredembodiment, the product is illuminated by a set of LEDs comprising oneor more LEDs emitting IR light of a wavelength within a range from 900nm to 960 nm, one or more LEDs emitting warm white light with awavelength within a range of 425 nm to 475 nm and one or more LEDsemitting cold white light with a wavelength within a range of 500 nm to700 nm. More preferably, the product is illuminated by a set of LEDscomprising one or more LEDs emitting IR light with a wavelength of 940nm to 950 nm, one or more LEDs emitting warm white light with awavelength within a range of 455 to 465 nm and one or more LEDs emittingcold white light with a wavelength within a range of 600 to 620 nm. TheLEDs may be used in high power output and may emit continuously or maybe pulsating. If pulsating emission is used, pulsation is preferablywith high frequency. The radiant output of the LEDs is preferably atleast 10 mW, more preferably, it is at least 50 mW, at least 100 mW, atleast 500 mW or at least 1 W. More preferably, the LEDs are high powerLEDs with a radiant output of at least 5 W, at least 10 W, at least 15W, at least 20 W, at least 25 W, at least 30 W, at least 35 W or atleast 40 W, in pulsed or continuous mode. In one embodiment, the LEDsare high power LED elements with a light intensity of at least 500mW/cm², at least 600 mW/cm², at least 700 mW/cm², at least 800 mW/cm²,at least 900 mW/cm² or at least 1000 mW/cm², in pulsed or continuousmode. Preferably, high power LEDs deliver in pulsed mode at least 1.5W/cm², at least 2.0 W/cm², at least 2,5 W/cm² or at least 3.0 W/cm². Thepower output of the LEDs may be adjusted in any convenient way. In oneembodiment, the output is adjusted per type of specific wavelength.

The current feeding the LED elements may be continuous or pulsed.Preferably, the feed is pulsed, because this will have a strongerpurifying or disinfecting effect. Most preferably, the feed is pulsedwith a high frequency, which refers to a frequency in the range of 10kHz to 1000 kHz. Preferably, the feed is pulsed at a frequency in therange of 100 kHz to 1000 kHz. More preferably, the feed is pulsed at afrequency in the range of 500 kHz to 1000 kHz.

The duty cycle of pulsation may vary. In one embodiment, the duty cycleof pulsation is 10% duty cycle and 10% power output. In anotherembodiment, the duty cycle of pulsation is 100% duty cycle and 100%power output. Several duty cycles may be combined. Therefore, in oneembodiment, the duty cycle in a first setting is 100% duty cycle and 10%power output and in a second setting is 100% duty cycle and 100% poweroutput.

All kinds of bacteria, both Gram positive and Gram negative, fungi,yeasts or parasites may be combatted using the method according to thepresent invention. Suitable examples include bacteria, yeast, fungi andparasites which belong to the genus, family or group Escherichia,Lactobacillus, Legionella, Leuconostoc, Listeria, Pediococcus,Salmonella, Shigella, Staphylococcus, Vibrio, Yersinia, Aspergillus,Peniciliium, Saccharomyces, Cryptosporidium, Giarda. In particular thespecies or isolates referred to as Escherichia coli, Listeriamonocytogens, Salmonella typhi, Shigella dysenteriae, Staphylococcusaureus, Vibrio cholera, Yersinia enterocolitica and Giardia lambia. AlsoESBL-forming bacteria may be combatted using the method according to theinvention.

Without wishing to be bound by theory, the inventor suggests that themethod according to the invention is particularly suitable to combatiron dependent bacteria, because it triggers a photoreceptor responsemechanism in iron dependent bacteria, such as E. coli, Salmonella,Listeria and Legionella. This turns off a ferric uptake repressor whichprevents aerobactin and specifically enterobactin from beingsynthesized, thereby inhibiting the assimilation of Fe²VFe³⁺ by the irondependant bacterial pathogen, which kills them.

Any product which needs disinfection or purification may be subjected tothe method according to the present invention, both organic andinorganic products, both gases, liquids and solids, both metalcomprising and metal-free products. Suitable examples of such productsinclude air, water, produce, food and plants. In particular, flowers,including cut flowers, and food, including vegetables, dairy products,grain products, meat and fish. Suitable examples of flowers includeflowers such as roses, gerbera's, tulips, lilies, chrysanthemums,orchids and gladiolus. Suitable examples of food include fruits, suchas, citrus fruits, stone fruits, in particular mango's, pears, apples,prunes, oranges, strawberries and bananas; dairy products, such as milk,cheese and butter; vegetables, such as sprouts, lettuce, cucumber,bananas, carrots and potatoes; grain products, such as maize, rice,wheat, barley, sorghum and oats; meat, such as beef, pork, lamb andpoultry; fish, such as salmon and tuna. The invention is particularlysuitable for disinfecting or purifying water sources or containers likesewage, drinking water, swimming pools, whirlpools and all applicationswhere water damp can be inhaled for risk of Legionella, such as wasteheat water supplies, water distribution networks, cooling towers,showers and Jacuzzi's. The method according to the invention can also beused to disinfect or purify animals, such as the ones which deliver themeat and fish as mentioned above; fruit, flowers and plants before theyare harvested to strengthen them and free them from microorganisms;surfaces, such as from working tables in shops and kitchens. In anotheraspect, the present invention relates to a device for applying themethod according to the present invention in all its embodiments for allthe products mentioned above. The device comprises IR LED elements and apower for the LED elements for the purification or disinfection of aproduct. At the same time, the product is also illuminated. The IR LEDelements are LED elements which emit light within a range from 900 to960 nm. Preferably, the LED elements are 940 nm LED elements.

In a preferred embodiment, the device further comprises white light LEDelements, for use in combination with the IR LED elements. Preferably,the white light LED elements comprise warm white light LED elements andcold white light LED elements. In one embodiment, the white light LEDelements comprise a 3000 K LED element. In another embodiment, the whitelight LED elements comprise a 6500 K LED element. The IR LED elementsand the white light LED elements may be arranged in any convenient way.In one embodiment, they are arranged in an alternating manner, i.e. anIR LED element is next to a white light LED element.

The number of IR LED elements and the number of white light LED elementsin the device may vary depending on the form of the device and theapplication for which they are used. In one embodiment, the number ofwhite light LED elements is larger than the number of IR LED elements.

The ratio of warm white light LED elements to cold white light LEDelements may also vary depending on the application and the form of thedevice. In one embodiment, the number of cold white light LED elementsis larger than the number of warm white light elements.

The device comprising the LED elements may have any suitable form. Inone embodiment, the device has an elongated form and the LED elementsare arranged in an elongated panel or string. The device may be used ina system for purifying or disinfecting a product, as mentioned in themethod according to the invention, in all its embodiments and for allthe products mentioned above.

Therefore, a system for purification of a product comprising an LEDlight source for emitting IR light onto the product is also part of thepresent invention. The IR light source is typically separated from theproduct. This may be done, for example, by a glass or synthetic materialwhich is transparent for IR light. The LED light source may be includedin a holder. In one embodiment, the LED light source is included in anelongated holder for a multiplicity of LED elements.

The product is preferably guided by a guide element. If the holder ofthe LED source is elongated, the guide element preferably stretches inthe direction of elongation of said light source. Holder and guideelement may be attached to each other. In one embodiment, the guideelement is a tube, for example a PVC tube.

The LED source in the system according to the invention may bepositioned in any suitable way. In one embodiment, the LED source is atopposite sites of the guiding element. Preferably, it is at two oppositesites of the guiding element, for example, above and below, or left andright. In one embodiment, the system further comprises a LED lightsource for emitting white light in combination with the IR light.

The system according to the present invention may be applied in variousapplications, including all the application mentioned before for themethod. In particular, in refrigerators for professional and domesticuse, purification of air, swimming pool purification, householdapplication and for purification of shower water. Of more particularinterest are applications where water damp can be inhaled for risk ofLegionella, such as waste heat water supplies, water distributionnetworks, cooling towers, showers and Jacuzzi's.

In applications involving a pool of liquid, such as a swimming pool, ortubs as may be used on bathroom shows or flower shows, a bypass systemmay be provided including a pump for the purpose of letting pass afraction of the amount of liquid in said pool per unit of time, so as tomaintain a proper sanitary level in said pool, in particular to theextend that addition of chemicals like chloric is not at all or to asignificantly lowered level required.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an example of a new device applying a new method of IRpurification using LED as a light source;

FIG. 2 exemplifies both part of said new device according to FIG. 1, andthe new method of applying IR light for the purpose of purification;

FIG. 3A,B,C shows Gerbera's and roses treated according to the method ofthe invention. Flowers treated according to the method of the inventionare on the right and controls are on the left.

EXAMPLES Example 1 System According to the Invention

FIG. 1 illustrates a disinfection system (1) in accordance with thepresent invention. A string of IR and warm and cold white light LEDscomprised in a casing form a lamp (2). Their radiation (4) illuminatesand disinfects the contents of a transparent tube (3), in this examplein the form of a PVC tube. The string of LED's stretches in thelongitudinal direction of the tube over the projected axis of the tube.Two lamps (2) are here included at opposite sides of a tube (3) in thesystem.

Example 2 Device According to the Invention

FIG. 2 illustrates a lamp with considerable expansion of the LED's widthwise of the lamp.

This lamp could also be used in the application of FIG. 1, however istypically intended for applications like preserving fresh produce,flowers and the like. It is as well suited for use in sewage stationswhere the lamp, rather than being immersed in a stream of water, may behung over such stream, either or not protected by an in between includedscreen, e.g. of glass or PVC.

The lamp includes IR LEDs separated by white light LEDs. In thisexample, the IR LEDs are directly flanked by so called cold white lightLEDs. The lamp according to the invention may easily be incorporated inexisting situations, e.g. for preserving food, in that the heightthereof is very limited, in the order of typical measurements of LED,whereas length and width may be dimensioned in accordance with thedisinfecting power required for the application.

The LEDs panel receive power from an electronic panel which allows tovary the power output of the LED light.

Example 3 Flower Treatment

Gerbera's and roses were treated according to the method of theinvention. They were illuminated 8 hours per day. The illumination was acombination of LEDs emitting IR light (940 nm), white light (460 nm) andwhite light (600 nm). Pulsed light with a pulsation frequency of 600 kHzwas used. As a control, gerbera's and roses were illuminated withfluorescent light for 8 hours per day. The test continued 24 days. Theresults are shown in FIG. 3 A-C. Controls are always on the left.

What is claimed is:
 1. A method for reducing number of microorganisms inor on a product selected from flowers, food, vegetables, meat, poultryor fish, and said method comprising: illuminating the product with acombination of one or more LED elements emitting infrared (IR) light ofa wavelength within a range of 900 to 960 nm, one or more LED elementsemitting light of a wavelength within a range of 425 to 475 nm, and oneor more LED elements emitting light of a wavelength within a range of600-620 nm.
 2. The method of claim 1, wherein the microorganisms areselected from the group consisting of bacteria, yeast, fungi andparasite.
 3. The method of claim 2, wherein the microorganism belong togroup of Escherichia, Legionella, Listeria, Aspergillus, Penicillium,Saccharomyces, Leuconosto, Lactobacllus, Pediococcus, Staphylococcus,Salmonella, Shigella, Vibrio or Yersnia.
 4. The method of claim 1,wherein radiant output of the LED elements is at least 10 mW.
 5. Themethod of claim 1, wherein current feeding to the LED elements is pulsedat frequency in the range of 10 kHz to 1 MHz.
 6. A device for reducingthe number of microorganism in or on a product selected from flowers,food, vegetables, meat, poultry, or fish using a combination of IR lightand visible light, wherein the device comprises one or more LEDelements, and a power for the LED elements, wherein the LED-elementscomprise a LED element emitting IR-light of a wavelength with a range of90 to 960 nm, a LED element emitting visible light of a wavelengthwithin a range of 425 to 475 nm, and a LED element emitting visiblelight of a wavelength within a range of 500 to 790 nm.
 7. The device ofclaim 6, wherein the LED-elements emitting visible light comprise a3000K LED element and a 6500 K LED element.
 8. The device of claim 6,wherein the number of LED elements in the device emitting visible lightis larger than the number of LED elements emitting IR.
 9. The device ofclaim 6, wherein the number of LED-elements emitting light of 425 to 475nm is larger than the number of LED elements emitting light of 600-620nm.
 10. A system for reducing the number of microorganism in or on aproduct selected from flowers, food, vegetables, meat, poultry or fish,said system comprising a device according to claim 6, wherein the ledsources are separated from the product by a glass or synthetic materialtransparent for IR light, wherein the LED sources are included in anelongated holder for multiplicity of LED elements, and wherein theproduct is guided by a product guide element stretching in the directionof elongation of the light source.
 11. The system according to claim 10,wherein the guide element is a tube.
 12. The system of clam 11, whereinan elongated holder is included at opposite sides of the tube.